Device for developing and fixing xerographic images



Feb. 20, 1962 w. LIMBERGER DEVICE FOR DEVELOPING AND FIXING XEROGRAFHIC IMAGES Original Filed April 12, 1957 my NN I. T IHHGL IIIIIIIIIIIII M HHJ I I l I I I I I I I I I I I I I n I rv qN BI; 1 l. HI+ |V. QM I m IIIIUMLV l Nib 9 19% LVH O\J X 91E a m H III e mm fi h I I H I 3 MN II Emmi om lI V SE E MWWI J I I I I I I I I I I I I. I I I I I I L II II II I I I I I I. l I I I I I I I I II l IIIII L @N R NN mfi NM WALTER LIMBERGER INVENTOR.

AGENT aren 3,021,818 Patented Feb. 20, 1962 Walter iiinbergel, Hamburg, Germany, assignor to Lurnoprint K.G., Hamburg, Ge many Original application Ar 2, 1957, Ser. No. 652,409. Divided and this application Sept. 1, 1959*, Ser. No.

illaims. (Cl. 118- 537) My present invention relates to a device for manufacturing copies using Xerographic layers as well as a method employing this device.

This application is a division of my application Serial No. 652,400, filed April 12, 1957, now Patent No. 2,961,993.

it is known to prepare copies using xerographic layers located on a layer support such as a sheet. Before the preparation of a copy, the xerographic layer must be formed in an electrode arrangement. The Xerographic layer is illuminated and covered with a powder containing pigment particles which adhere to the configuration of the latent electrostatic image of the master in the xerographic layer. To produce the copy, the pigment particles are fused into the xerographic layer.

The manufacture of copies using Xerographic layers has considerable advantages, although the use of this method has not been previously possible on a large scale since the apparatus required is extremely complicated and since no readily operable device has been known to combine the several processes of the method. Even the distribution of the powder on the latent electrostatic image requires an exact and fine determination of powder dispersal which could not be carried out in known devices without a considerable consumption of the powder. The measuring of the amount of powder and the particular distribution of the powder could only be controlled heretofore with difiiculty and upon distribution the powder led to substantial soiling of the whole apparatus.

The invention the object of providing a readily operable device w l. possible the preparation of copies with nerogrr hic layers without material powder and provides that in operation the special requirements of particular images are taken into the plate is provided "t a tensioning device adapted to clamp the layer support or sheet between the base plate and itself, the occupied by the layer support on the base plate being covered at a certain distance from the layer supports at the same time means are provided for guiding the coating powder to the developing space between the layer support and the cover without removing the cover. The to oning device is constructed as a frame and has a dish-line lower part to which a handle is secured. Over the dish-lilte lower part is located a tensioning rim for the layer support which has a certain height and serves as a collecting rim for the powder grains on distributing the pigment particles on the latent electrostatic image.

Advantageously, the tensioning device is constructed in the form of a box with a closure device over the tensioning rim, so that the manufacture of copies is possible with ordinary illumination. In particular, this closure device is constructed as a slidable cover and is made transparent. On the closure device is located a preferably removable supply container for the powder.

T he supply container for the mobile pigment carriers or toner particles communicates through one or more openings with the inside of the box-like tensioning device and is arranged directly on a side of the box-like frame.

In the construction of the tensioning device as a dishlike hand apparatus provided with a handle, the developer supply device is arranged inside the handle which is provided with an enlarged portion at its end and adjacent to the tensioning device that one or more openings can be distributed over the whole facing side of the tensioning device. in a preferred embodiment, one or more openings are located above a step-like Wall part of the tensioning device on which the Xerographic layer support lies or in which it is stretched, so that the developer is reliably supplied through the opening or openings to the upper surface of the sheet which is provided with the nerographic layer.

The opening or openings between the supply container for the developer and the inside of the box-like frame are, advantageously, closable. The closure may be eiiected from the outside, in particular from the handle, and the closure means can be constructed for example in the form of one or more pivot flaps arranged in the opening or openings.

Preferably the invention includes a pistol grip construction of the handle of the frame with a setting member similar to a trigger for operating the closure of the opening or the openings between the supply container for the toner and the inside or" the frame. It may be mentioned that these openings can be arranged on several sides of the box-like tensioniug device.

it should be noted that the developer consists of mobile pigment carrier particles, particularly glass spheres, and pigment particles which are transmitted from the carrier particles to the latent electrostatic image, and that in using the toner, only the pigment particles of the developer are consumed by transfer to the image, but not the carrier particles.

According to the invention, the supply container for the developer is divided into two chambers, one of which serves for receiving the carrier particles and the other for receiving the toner. These chambers are connected together in a separable manner, wherein the closure is constructed as a valve or slide-plate or the like which is itself operable by a setting member on the handle or by a movement of the handle. In a particularly preferred construction, both chambers are arranged one behind the other in the handle of a dish-like device, so that the chamber with the carrier parti les is adiacent to the box-like frame and the cha rber with the toner is adjacent to the carrier-particle chamber but opposite the frame and extends into the handle of the apparatus.

in using the device according to the invention, the manufacture of copies with xerographic layers is considerably facilitated, since the layer support need only be stretched in the clamping device, which is subsequently moved into different cooperating processing devices provided with slots.

One of these devices is the forming device, which consists of an electrode arrangement. It is so constructed that over the tensioning device a number of electrodes having small radii of curvature (e.g. wires) are arranged, whereas the counter-electrode is disposed under the tensioning device. The potential of this counter-electrode is supplied, on inserting the tensioning device, into the slot of the forming device. Preferably, the lower electrode is at ground potential so that the charged plate is arranged within the tensioning device.

An illuminating device which is likewise provided with a slot into which the box-like tensioning device according to the invention is inserted, in order to expose the nerographic layer.

On these two devices, are provided which co-operate with special means provided on the closure device to ensure, for example, that the closure device of the tenand illuminating apparatus and upon removing the tensioning device.

. The forming and illuminating apparatus can be used with a plurality of tensioning devices according to the invention, since they are in use only for a short time for preparing a copy. The tensioning devices themselves serve for distributing the coating powder of the latent electrostatic image and in one embodiment also as a fusing device. By this, it is ensured that a particularly fine distribution of the coating powder on the electrostatic image will result, and that no movement of the electrostatic layer is required before fusing of the pigment particles.

Further advantages and features of the invention will appear from the specification of the embodiments illustrated in the accompanying drawing. In the drawing:

FIG. 1 shows a section through a device constructed according to the invention along the line II of FIG. 2; and

FIG. 2 shows a front view of the device according to FIG. 1 from above.

The hand-operable device illustrated in the drawing consists of a box-like tensioning device 22 and a substantially horizontal actuating handle 23 arranged on this tensioning device.

The tensioning device includes a frame 24, a base plate 25 and a removable cover 26. The cover 26 is transparent and made, for example, of red glass or a transparent synthetic material, so that illumination of the sheet 27 lying on the tensi'oning device 22 is lprevented when the cover is in place, but observation of the layer support 27 is possible. The cover is adjustable in guides 28, 29 which are arranged on the longitudinal sides of the frame. An abutment 30 or a handle 31 serve for automatic displacement of the cover 26.

The cover is made box-like so that the upper side of the cover has a greater spacing above the layer support 27 corresponding to the thickness of the frame 24. This construction of the cover has the advantage that the rigidity of the cover is increased and that, because of the greater distance of the cover from the layer support, soiling of the transparent cover by'the toner is prevented.

The frame 24 is preferably arranged to be at least partly removable from the base plate 25, so that upon insertion of the layer support 27, stressing of the latter and the base plate 25 by the frame 24 is possible. The frame 24 and the base plate 25 are connected together by the hinge 32. The base plate 25 preferably consists of electrically conductive material, so that it can serve as the counter-electrode upon insertion of the device in the forming device. Moreover, the base plate 25 is made of good heat-conducting material so that heating of the stretched layer support 27 through the base plate 25 can occur. This heating is effected preferably by a separate heating apparatus in which the unit is inserted or by a heating device not shown in detail and arranged directly beneath the base plate 25.

The handle 23 is secured by means of an extension 33 to the frame 24 or to the base plate 25. Between the shank 34 of the handle and the frame part 35 facing the handle, a chamber 36 extending over the width of the frame is arranged which serves for receiving the carrier particles 37 of the developer, for example glass spheres. The chamber 36 can be so arranged that it extends into or lies fully in the shank 34 of the handle, wherein guides are provided merely at the side/facing the frame 34 or the frame part 35 for uniform distribution of the toner at least on the side facing the frame. 7

The shank 34 is made hollow so that a chamber 38 is produced which serves for receiving the toner for the developer. The chamber 33 is separated from the chamber 34 by an intermediate wall 39. In the intermediate wall, aclosable opening 40 is located through which toner can be supplied from the chamber '38 to the chamber 36.

sioning device is open upon insertion into the forming In the embodiment shown, the opening 40 is closed by a valve member 41 of truncated conical form which abuts with its conical surface a correspondingly shaped opening. The closed position of the valve member 41 is ensured by a spring 42 which can engage the valve member 41 directly or operate through a rod 43 which is arranged on one end of the valve member 41. On the other end of the rod 43 is located an operating knob 44 which lies within an opening 45 in an end cap 46 of the hand 23. The spring 42 is advantageously arranged between the actuating knob 44 and the closure 47 and the chamber 38.

The chamber 38 includes a filling opening through which toner can be charged to the chamber 38. This opening is not shown in detail in the embodiment illustrated. For example, it can be formed by'the removable arrangement of the wall 47 which can be opened by removal of the end cap 46.

For providing a connection between the chambers 38 and 36, a pressure knob 44 is operated. By shifting the rod 43, the valve member 41 with its end of greater 'cross-section is pushed in the chamber 36, 'so' that the the pigment particles are replenished.

Between the chamber 36 and the inside of the boxlike tensioning device 22 is located a plurality of openings 48, through which the developer can flow in the direction of the arrows 49 to the stretched layer support 27 and in the reverse direction into the chamber 36. The openings 43 are so made that a uniform distribution over the whole width of the layer support is ensured. For this purpose, the outlets of the openings 48 are widened.

The openings 43 are made closable, so that escape of the developer from the chamber 36 can be prevented. Closure can be effected, for example, by flap-like parts in the separate openings 48 which are operable from outside. The device illustrated includes another construction in which closure of the openings 48 can be effected by a flap 51 (shown in dotted lines in PEG. 1) pivotally arranged on the upper wall 59 of the chamber 36 with a web 52 arranged perpendicular to the axis of the openings 48. The arrangement is so made that the web 52 engages in a slot which runs in front of the openings 48 on the side facing the handle 23.

When producing an image, a layer support 27 with a 'xerographic layer is stretched by the frame 24 on the base plate 25. The openings 43 are closed. The device, which the operator holds by the handle 23, is inserted into a forming device, during the insertion the cover 26 is moved back toward the handle by contact of the abutment 3% with a corresponding projection. At the same time, the base plate 25 is connected to the forming circuit whereupon charging of the Xerographic layer occurs. On

removing thedevice, the cover is returned to its closed position either automatically or by means of the handle 31, so that no illumination of the layer support occurs.

The device is then inserted into the illuminating apparatus, wherein the cover 26 is opened in the same way and is closed on removal.

After the illumination, when the device has been removed from the illumination device, the openings 43 are opened and the developer is supplied through these openings to the Xerographic layer with the latent electrostatic image. By tilting the apparatus, it is possible to distribate the developer uniformly over the Xerographiclayer to make visible the image by the layer of pigment particles. This process can be observed through the trans parent cover 26, so that during this process very section of the image can be developed to a greater or lesser extent by appropriately distributing the developer by corre sponding inclination of the device to those parts of the image which are to be developed the stronger. It is thus possible by continuous observation of separate parts of the image to treat these parts difierently.

After rendering the latent electrostatic image visible, the developer is returned through the openings 48 to the chamber 36 by tilting the device, whereupon the openings 4% are closed and either a heating device arranged beneath the base plate 25 is operated or the device itself is inserted into a heating device whereby fixation occurs by heating from above after removing the cover.

What I claim is:

l. A device for developing a latent image on a xerographic sheet, comprising a mobile assembly including substantially closed box capable of being opened, said box being provided with a substantially horizontal base plate, a hollow handle extending substantially horizontally from said box, said handle being provided with an internal partition dividing its interior into a first chamber close to said box and a second chamber remote from said box, said second chamber containing a supply of developing pigment, said partition being provided with a first passage interconnecting said chambers, means in said box for fastening said sheet to said base plate, a supply of mobile pigment carriers in said first chamber, said first passage being narrow enough to confine said carriers to said first chamber while permitting the transfer of developing pigment from said second chamber to said first chamber upon a slight tilting of said assembly, closure means forming an elevated second passage between said first chamber and said box for enabling the transfer of said pigment and said carriers from said first chamber to the interior of said box and vice versa upon a more extensive tilting of said assembly, shutter means in said first passage, and shutter-control means externally of said handle operatively linked with said shutter means for temporarily blocking the transfer of pigment between said chambers during said more extensive tilting.

2. A device according to claim 1 wherein said first passage is a tapered opening in said partition diverging toward said first chamber, said shutter means comprising a substantially conical valve member received in said opening and a stem on said valve member traversing said handle longitudinally by way of said second chamber, said shutter-control means comprising a spring-loaded knob on a projecting extremity of said stem.

3. A device for developing a latent image on a xerographic sheet, comprising a mobile assembly including a substantially horizontal base plate, a frame hingedly connested with said plate and adapted to clamp said sheet between itself and said plate, a cover above said plate removably secured to a side of said frame remote from said plate, thereby forming a developing space above said plate, container means at a side of said frame and forming a storage space adjoining said developing space substantially horizontally, partition means in said container means subdividing said storage space into a first chamber next to said developing space and a second chamber remote from said developing space, said frame being provided with at least one opening connecting said first chamber with said developing space, said partition means being provided with a passage interconnecting said chambers, said first chamber containing a supply of mobile pigment carriers, said second chamber containing a supply of developing pigment adapted to reach said first chamber through said passage upon a slight tilting of said assembly, said opening being so located as to enable the transfer of pigment carriers and pigment between said first chamber and said developing space only upon a more extensive tilting of said assembly, shutter means in said passage for preventing the admission of pigment carrier to said second chamber at all times and for temporarily blocking the transfer of pigment between said chambers during said more extensive tilting, and shuttercontrol means on the exterior of said container means connected with said shutter means.

4. A device according to claim 3, further comprising closure means at said opening selectively operable to shut said developing space completely against said storage space.

5. A device according to claim 4 wherein said closure means comprises flap means hingedly connected to said container means and provided with an extension retractably insertable into said opening.

6. A device according to claim 3 wherein said con tainer means comprises a substantially cylindrical housing fixedly secured to said base plate as a handle for said assembly.

References Cited in the file of this patent UNITED STATES PATENTS 2,550,724 Sahel et a1. May 1, 1951 2,550,738 Walkup May 1, 1951 2,635,046 Sabel et al. Apr. 14, 1953 2,877,132 Matthews Mar. 10, 1959 

